playfair密碼java實現

標籤：new   playfair   對稱式加密   密碼編譯演算法   playfair密碼   

這次，使用java來類比現實playfair密碼加密解密過程

import java.util.HashSet;import java.util.Scanner;public class Test1 {    public static char a[][] = new char[5][5];    public static String Encryptkey = "";    public static void main(String[] args) {        // TODO Auto-generated method stub        Scanner input = new  Scanner(System.in);        System.out.println("Please input the key");        String key = input.nextLine();        System.out.println("Please input the clear key");        String clearkey = input.nextLine();        System.out.println("Please input the signture key");        String signture = input.nextLine();        System.out.println("Output the key matrix");        Keymatrix(key);        OutputMatrix();        System.out.println("Encrypt");        Encrypt(clearkey, signture.toUpperCase());        Dncrypt(Encryptkey);    }    private static void Dncrypt(String encryptkey2) {        // TODO Auto-generated method stub        String Dncryptkey = "";        int m=0, n=0, o=0, p=0;        for(int i=0; i<encryptkey2.length(); i+=2) {            for(int j=0; j<5; j++) {                for(int k=0; k<5; k++) {                    if(a[j][k] == encryptkey2.charAt(i)) {                        m=j;                        n=k;                    }                    if(a[j][k] == encryptkey2.charAt(i+1)) {                        o=j;                        p=k;                    }                }            }            if(m==o) {                Dncryptkey =Dncryptkey + a[m][(n+4)%5] + a[o][(p+4)%5];            }            else if(n==p) {                Dncryptkey =Dncryptkey + a[(m+4)%5][n] + a[(o+4)%5][p];            }            else {                Dncryptkey =Dncryptkey + a[o][n] + a[m][p];            }        }        System.out.println(Dncryptkey);        System.out.println();    }    private static void Encrypt(String clearkey, String signture) {        // TODO Auto-generated method stub        String Upperclearkey = clearkey.toUpperCase();        String formatkey = "";        for(int i=0; i<Upperclearkey.length(); i++) {            if(Upperclearkey.charAt(i)>=‘A‘ && Upperclearkey.charAt(i) <‘Z‘) {                formatkey+=Upperclearkey.charAt(i);            }        }        while(isOverFlow(formatkey)) {            formatkey = addSignture(formatkey, signture);        }        if(formatkey.length()%2 !=0) {            formatkey += signture;        }        getEncrypt(formatkey);    }    private static void getEncrypt(String formatkey) {        // TODO Auto-generated method stub        int m=0, n=0, o=0, p=0;        for(int i=0; i<formatkey.length(); i+=2) {            for(int j=0; j<5; j++) {                for(int k=0; k<5; k++) {                    if(a[j][k] == formatkey.charAt(i)) {                        m=j;                        n=k;                    }                    if(a[j][k] == formatkey.charAt(i+1)) {                        o=j;                        p=k;                    }                }            }            if(m==o) {                Encryptkey =Encryptkey + a[m][(n+1)%5] + a[o][(p+1)%5];            }            else if(n==p) {                Encryptkey =Encryptkey + a[(m+1)%5][n] + a[(o+1)%5][p];            }            else {                Encryptkey =Encryptkey + a[o][n] + a[m][p];            }        }        System.out.println(Encryptkey);        System.out.println();    }    private static boolean isOverFlow(String formatkey) {        // TODO Auto-generated method stub        for(int i=0; i<formatkey.length() - formatkey.length()%2; i+=2) {            if(formatkey.charAt(i) == formatkey.charAt(i+1)) {                return true;            }        }        return false;    }    private static String addSignture(String formatkey, String signture) {        // TODO Auto-generated method stub        String temp = "";        for(int i=0; i<formatkey.length() - formatkey.length()%2; i+=2) {            if(formatkey.charAt(i) == formatkey.charAt(i+1)) {                temp = temp + formatkey.charAt(i) + signture.charAt(0) + formatkey.charAt(i+1);            }            else {                temp = temp + formatkey.charAt(i) + formatkey.charAt(i+1);            }        }        return temp;    }    private static void OutputMatrix() {        for(int i=0; i<5; i++) {            for(int j=0; j<5; j++) {                System.out.print(a[i][j]+"  ");            }            System.out.println();        }        System.out.println();    }    private static void Keymatrix(String key) {        // TODO Auto-generated method stub        HashSet<Character> hs = new HashSet<Character>();        String formatkey ="";        String Upperkey = key.toUpperCase();        for(int i=0; i<Upperkey.length(); i++) {            if(Upperkey.charAt(i) >=‘A‘ && Upperkey.charAt(i) <‘Z‘) {                if(!hs.contains(Upperkey.charAt(i))) {                    hs.add(Upperkey.charAt(i));                    formatkey+=Upperkey.charAt(i);                }            }        }        for(char i=‘A‘; i<‘Z‘; i++) {            if(!hs.contains(i)) {                formatkey+=i;            }        }        int m = 0;        for(int i=0; i<5; i++)            for(int j=0; j<5; j++) {                a[i][j] = formatkey.charAt(m);                m ++;            }    }}

著作權聲明：本文為博主原創文章，未經博主允許不得轉載。

playfair密碼java實現